1. Field of the Invention
This invention relates to clips that connect main beams together, end-to-end, in a grid structure for a suspended ceiling.
2. Background Information
Suspended ceilings having metal beams or runners that form grids to support panels are well known. Such grids have main beams or runners, and intersecting cross beams or runners. The beams are formed generally of flat sheet metal folded into an inverted T-shape, but in some instances are of extruded metal, such as aluminum. The main beams are secured end-to-end by connectors. The main beams are suspended from the structure ceiling by wires. The crossbeams are connected end-to-end through slots in the main beams and are supported by such main beams.
The main beams, which run parallel to one another, are generally spaced 48" apart. Crossbeams are connected to the main beams to form either 24".times.24" rectangular openings, or 24".times.48" openings, which receive the laid-in panels.
Such main beams in a suspended ceiling are subjected primarily to tension, compression, and bending stresses, and occasionally to twisting forces. The function of the connectors which join the generally 12 foot lengths of main beams together longtudinally is to maintain adequate strength and alignment.
Since the beam connections are end-to-end, the flanges, web, and bulb of each beam abuts the other, so that the connector has little to resist in compression. Of course, the connector must keep the ends of the beams aligned. Fire relief notches can be cut into the beam proper to provide for expansion relief in case of a fire, since there is no give at the beam end.
With respect to tension or pulling apart of the connection longitudinally, the connector is the sole means to resist such tension at the connection.
With respect to the resisting and bending, the connector, along with the beam-ends, provides resistance to such bending.
The connectors must resist the occasional twist.